The 4th and 5th centuries are an epoch in which Church crosses from a persecution's period to its protection, happened by political authorities and especially by the imperial principle. During this season, the Christianity's foundations were set by the action of the ecumenical Church teachers. Nevertheless, Byzantine Empire also formed its function's principles. These two realities were joined, interacted and created the Byzantine culture. The current book is an historical and theological research of this period drawing conclusion from the vivid scriptures of great Fathers.